title: Isolation and expression analysis of partial sequences of heavy metal transporters from Brassica juncea by coupling high throughput cloning with a molecular fingerprinting technique.
abstract: Heavy metal transporters play a key role in regulating metal accumulation and transport in plants. These are important candidate genes to study in metal tolerant and accumulator plants for their potential use in environmental clean up. We coupled a degenerate primer-based RT-PCR approach with a molecular fingerprinting technique based on amplified rDNA restriction analysis (ARDRA) to identify novel ESTs corresponding to heavy metal transporters from metal accumulator Brassica juncea. We utilized this technique to clone several family members of natural resistance-associated macrophage proteins (NRAMP) and yellow stripe-like proteins (YSL) in a high throughput manner to distinguish between closely related isoforms and/or allelic variants from the allopolyploid B. juncea. Partial clones of 23 Brassica juncea NRAMPs and 27 YSLs were obtained with similarity to known Arabidopsis thaliana and Noccaea (Thlaspi) caerulescens NRAMP and YSL genes. The cloned transporters showed Brassica-specific changes in domains, which can have important functional consequences. Semi-quantitative RT-PCR-based expression analysis of chosen members indicated that even closely related isoforms/allelic variants of BjNRAMP and BjYSL have distinct tissue-specific and metal-dependent expressions which might be essential for adaptive fitness and heavy metal tolerance. Consistent to this, BjYSL6.1 and BjYSL5.8 were found to show elevated expressions specifically in cadmium-treated shoots and lead-treated roots of B. juncea, respectively.
authors.affiliation: Department of Biotechnology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700019, India.
authors.forename: Soumita
authors.initials: S
authors.lastname: Das
authors.forename: Monali
authors.initials: M
authors.lastname: Sen
authors.forename: Chinmay
authors.initials: C
authors.lastname: Saha
authors.forename: Debjani
authors.initials: D
authors.lastname: Chakraborty
authors.forename: Antara
authors.initials: A
authors.lastname: Das
authors.forename: Manidipa
authors.initials: M
authors.lastname: Banerjee
authors.forename: Anindita
authors.initials: A
authors.lastname: Seal
mesh_terms: D001483:Base Sequence; D002104:Cadmium / Q000378:metabolism; D003001:Cloning, Molecular / Q000379:methods; D016172:DNA Fingerprinting / Q000379:methods; D018506:Gene Expression Regulation, Plant; D026901:Membrane Transport Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D019216:Metals, Heavy / Q000378:metabolism*; D008969:Molecular Sequence Data; D009149:Mustard Plant / Q000235:genetics* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D026901:Membrane Transport Proteins; D019216:Metals, Heavy; D002104:Cadmium